AliSadr Cave, Hamedan. Iran

Alisadr is the world's biggest water cave, where you sit in a boat and watch the view. This cave is located at 48°18'E 35°18'N, in the southern part of Ali Sadr village. The cave is entered at the side of a hill called Sari Ghiyeh which also includes two other caves called Sarab and Soubashi, each 7 and 11 kilometers from Ali Sadr Cave. Apparently, the water in Ali Sadr cave stems from a spring in Sarab